Page 39 - Electrostatics-11

© GC Shiba

∆
Instantaneous acceleration: = lim ( ) =
∆→0 ∆

Uniformly accelerated motion: The motion is said to be uniformly accelerated if

the velocity changes equally in equal interval of time.

For uniformly accelerated motion, a = constant and

+
=

2

th
Displacement of a body during n second of its motion

Displacement of a body is given by

1
2
= +
2

Put t = n and t = n-1 in turn

1
2
= +

2
1
2
And, −1 = ( − 1) + ( − 1)
2
th
Now, the displacement in the n second is ,

ℎ = − −1

1 1
2
2
= + − [ ( − 1) + ( − 1) ]
2 2

∴ = + ( − )

Q. A body dropped from the top of a tower falls through 25 m during the last
2
second of its motion. Find the height of the tower. ( g = 10 m/s ) Ans: 45 m

16 Mechanics